Administrator of



LIVINGSTON c rronn, oEJEEsEY crrv,

ATEN'r @O-Errca NEW JERSEY, ADMINISTRATOR F KARL HEUMANN, DECEASED, ASSIGNOR 25 atives with caustic-soda or caustic potash at TO THE BADISCHE, ANILIN-AND soDA'EAuRiK, or LUnwIcsnnFEN, GERMANY.

Paocess OF MAKENG mo srncrrrcnrron forming part of Letters 2 Application filed December 1'7, 1897.

To all whom it may concern:

Be it known thatKARL HEUMANN,C1906&S6(L late of Zurich, Switzerland, did invent a new and useful Improvement in the lllanufacture of Indigo Colorin lllatters, of which the fol" lowi ng is a specification and for which patents were obtained in the following countries: England, No. 8,726, dated June 5, 1890; ltaly, XXI, 29,596, LVIII, 1S8, dated-September 3O, :0 1890; Germany, No. 63,310, dated March 10, 1891; France, No. 206,567, dated March 1 1891; Belgium, No. 94,447, dated April 15, 1891; Spain, No. 11,937, dated April 25, 1891; Austria, No. il/2,240, dated August 17, 1591; Hungary, XXV, 2,123, dated August 17, 1891, and Russia, No. 19,707, dated October-3, 1892. In several applications for patent processes are described for the manufacture of indigo coloring-matters invented by the late Professor Karl Heumann, (see German Patents No. 5%,626, of'Ma-y 6,1890; NO. 58,276,013 August 15-, 1890; No. 61,712, of December 30, 1890, and No. 63,309,0f March 10, 1890,) which consists in treating various 1 glycocol derivasuitable temperatures and oxidizing the leuco compounds so obtained to convert them into the coloring-matters.

. This inventionconsists of an improvement 0 in the first part of'the. above-named process, whereby a bettenyield can be obtained. he improvement consists in using instead of. caustic soda or caustic potash alone or mixed with one another either orboth of these alka- 35 lies admixed'with quicklime. J

In all the processes above referred tothisinventor has found that it is advantageous to add fresh q'uicklime to the caustic alkali-used zoo (COLORING-MATTERS.

atent No. 617,652, dated January 10, 1899.

Serial No. 662,306. (No specimens.)

sequently of the indigo coloring-matter, is in each case obtained.

. The following example will serve to show how this invention is carried into effect in practice: 5

Hi together one hundred parts of orthotolyl-glycocol, four hundred and fifty parts of caustic potash, (or of amixture of equal. parts of caustic potash and caustic soda,) and. one hundredand thirty parts finely-powdered fresh. quicklime. Heat these, while stirring quickly, to 270 centigrade, excluding the air as far as possible, raise the temperature within about ten minutes from 270 to 300 centigrade, allow the melt to cool, dissolve in water, preventing contact with the air as far as conveniently possible, filter till free from lime and pass astream of air through the solution until no further precipitate of the coloring-matter takes place, filter, wash with water, with a little hydrochloric acid, and finally again with water, and dry. This addition of quicklime to the melt can be made in all cases without regard to the glycocolused. The quantityof quicklimeisso chosen thata melt which is not too thickto be readily stirred is obtained.

What is claimed is-.

The, improvement in the process of manuteetering-indigo coloring-matters from glyco- '70 col derivatives, consisting in adding quicklime to the caustic alkaline melt,'in which the glycocoi'derivatives are treated, substantially as described.

, LIVINGSTON GIFFORD, Administrator of the estate ofKa'rl IIe-wmmm,

deceased.

Witnesses:

M. WILSON,

in the melt, the beneficial edect being that a 40 higher yield'of the leucocompound, and con- J. GREEK. 

